With the development of the liquid crystal display (LCD) technology, the desired resolution of the liquid crystal display is increasingly high, while the desired frame of the module is increasingly narrow. Therefore, more wires are distributed in the wiring region, resulting in increased density. In view of technical bottlenecks in the process such as requirements on minimum wiring width and spacing, double-layer scanning lines technology has been applied widely. In general, two different metal materials are used for manufacturing the scanning lines, but since the resistivity of the two metal materials is different, it is important to match the resistance values of the two metal scanning lines. Thus, line width and film thickness of the scanning lines have to be calculated accurately in the design process and to be controlled strictly in the manufacture process. However, fluctuations and errors in the design or manufacturing process may cause mismatch between the resistance values of the two layers of scanning lines, resulting in different feed-through voltages of TFTs (Thin Film Transistors), and poor uniformity of a display. For example, horizontal strips of a gray scale image may appear in the display, which degrades the image display quality.
In order to solve the problems above, conventional techniques promote a method that uses two kinds of metal wirings for each of the scanning lines to reduce the difference caused by the two materials themselves. When the method is used in practical design, the resistance of each wiring has to be simulated accurately to control the resistance of each wiring electrode. Since each gate electrode is formed by two kinds of metal wirings, and via-hole connections are required in the manufacture process, the complexity of the manufacturing process is increased and the production yield is affected. Also, although the resistance of each scanning line is simulated, actual fluctuations in the manufacturing process may result in resistance mismatch, and the displayed image quality is poor.
Chinese patent application publication No. CN1825415A, titled “LIQUID CRYSTAL DISPLAY DEVICE PERFORMING DOT INVERSION AND METHOD FOR DRIVING THE SAME” discloses various methods for driving an LCD panel.